Line feed mechanism



May 30, 1967 c. H. CLARK ETAL.

LINE FEED MECHANISM 3 Sheets-Sheet l Original Filed Oct. 25. 1962INVEN'I'ORS C/.AYro/v h'. CLARK Do/vALo J rEFA/v/K A ORNEY5 May 30, 1967LINE FEED MECHANISM Original Filed Oct. 25, 1962 3 Sheets-Sheet 2INVENTORS CLAYTo/v H.` CLARK DONA/ 0 J. STEFAN/K A ORNEYS C. H. CLARKETAL 3,322,316`

May 30, 1967 c. H. CLARK ETAL LINE FEED MECHANISM 5 Sheets-Sheet 5Original F'iled Oct. 25. 1962 INVENTORS C1A rolv H Ik am'. [MMM By j MJA ORNEYS 3,322,316 LINE FEED MECHANISM Clayton H. Clark, Mundelein, andDonald J. Stefaniir,

Berwyn, Ill., assignors to SCM Corporation, a corporation of New YorkOriginal application st. 2S, 1962, Ser. No. 233,109, now Patent No.3,291,909, dated Dec. 13, 1966. Divided and this application May 2,1966, Ser. No. 546,917

7 Claims. (Cl. 226-141) versatile and readily adapted for use with otherdatal processing page recorders su-ch as electric typewriters andconventional telegraph printers.

The improvements of this present invention involve the mechanicalcomponents to accomplish selectively variable record paper feed whichwill be referred to as line feed hereinafter. As compared withthe linefeed mechanism described in co-pending application Ser. No. 184,820,filed April 3, 1962, now Patent No. 3,280,256, the line feed mechanismhas been substantially improved and made more versatile by utilizing amotor driven power feed rather than a solenoid operated feed and byusing a novel controllable line feed to enable variation in the numberof lines the record is fed during each feed operation, the powerrequired being proportional to the line feed desired.

Accordingly, a primary object of this invention resides in the provisionof an improved line feed mechanism for use in data processing equipmentsuch as page printers or telegraph typewriters and the like.

Still another object resides in the provision of an improved pageprinter with novel record medium line feed mechanism powered from apower shaft driven, rotatable start-stop cam assembly and a cam followerlinkage operating a pawl and ratchet transmission to the record engagingfeed components, having means to vary the magnitude of the actual strokeof the cam follower as imparted by the power driven cam assembly. Inconjunction with the foregoing object, it is a further object toaccomplish the start-stop line feed cycle by a solenoid which willenable associated equipment control circuitry to automaticallyaccomplish a line feed cycle energization of the line feed solenoid forevery carriage return operation of a page printer.

A still further object resides in a provision of a novel selectivelyvariable record medium line feed mechanism for use in typing or printingmechanism. In connection with the preceding object, a further objectresides in providing an improved line feed mechanism in which the powerstroke is selectively variable.

Further novel features and other objects of this invention will becomeapparent from the following detailed description, discussion and theappended claims taken in conjunction with the accompanying drawingsshowing the subcomponent structures and units constituting the presentinvention, in which:

FIGURE 1 isla front perspective skeleton view illustrating the majormechanical components of a drum printer which incorporates the line feedmechanism of the Vpresent invention. Although this view omits manydetails utilized in such a drum printer they are not deemed necessary toan understanding of the present invention;

FIGURE 2 is a reduced scale, side View of the complete United StatesPatent O rotational mounting, one paper feed Wheel and the clockassembly with its adjustable reading head timing support disc;

FIGURE 4 is a detail end View of the reading head timing support disctaken on line 4-4 of FIGURE 3;

FIGURE 5 is a partially sectioned elevation view of the lower half ofthe print drum illustrating the relationship between the print drum, theframe end supporting plates and the paper feed components;

FIGURE 6 is a detail end view looking at the righthand side of theprinter and illustrating the line feed solenoid and the relationshipbetween its armature lever and the positive line feed clutch;

FIGURE 7 is a right-hand end View illustrating the mechanical linkagebetween the line feed cam (shown in FIGURE 6) and the line feedactuating pawl mechanism; and

FIGURE 8 is an exploded perspective view illustrating the means by whichthe total line feed power stroke may be varied to accomplish differentamounts of paper feed.

GENERAL The major mechanical components of a drum form of page printer,including the line feedA arrangement pertinent to this invention, areshown in the skeleton arrangement of FIGURE 1 as an example of 4utilityof the line feed mechanism. It will be generally described beforeproceeding with a detailed description of the line feed mechanism. Theframe structure of the printer, the ribbon feed and reverse mechanismand various controls are not shown in FIGURE 1, however a representativesomewhat similar drum printer assembly can be found in co-pendingapplication Ser. No. 184,820 to which reference may be had, ifnecessary, for a complete understanding of the printer construction.

The printer is designed primarily for use in a sendreceive tele-printerset, being used for page copymonitoring and/'or page copy receiving.

A single hammer printer embodiment is capable of operating at nominalaverage speeds up to and including 200 w.p.m. and if dual print hammersare utilized, with double step character spacing, average operationalmaximum speed is appreciably increased, up to at least 400 w.p.m.Further multiplication of the number of hammers results in attaining ofhigher operational speeds which will necessitate related increase inrates of line feed.

In general, the printer mechanics 5t) employs a motor driven rotatingtype drum 52 which, for standard cornmunications printers, will have 72rings of type, each type having the 52 standard communications symbols.The drum and its construction is fully described and claimed in theaforenoted pe-nding application Ser. 184,- 820 or divisional thereofand, per se, are not a part of the present invention.

Characters on each ring of type are similarly placed in binary orderaccording to the Baudot code for the character, each character beingassigned a position in -a 64 count binary progression so that theprinter electronics can compare an incoming charater ode against a odecombination representative of the series of pulses subsequent to anindex position which indicates the physical position of the drumcharacters relative to that indexing position. When comparison matches,coincidence, the electronic logic can determine exactly when to actuatethe print hammer for printing the character when the drum rotates thatcharacter in front of the print hammer.

' The complete dum 52 includes on is cylindrical periphery a pluralityof different horizontal lines of identical in- -formation symbols, for aconventional telegraph printer, seventy-two (72) identical symbols,e.g., seventy-two As, constituting one line of identical character typefaces extending along the cylindrical drum periphery parallel to thedrum axis. The drum 52 and an attached drum position clock wheel 58 arecontinuously rotated by a printer motor B1 when the motor is running.Related printer electronics are described in parent application 233,109.

As depicted in FIGURE l, a print hammer carriage assembly S4 is mountedfor stepped spacing movement in a horizontal path from left to right andreturn movement from right to left in front of the type drum 52. Theillustrated hammer carriage assembly 54 is universal in nature and canaccommodate one or two print hammers with associated operatingcomponents.

The pri-nting mechanism includes an induction pulse clock assembly 56which supplies one index pulse and a series of character position pulsesto the printer electronics, representative of drum rotational position.Since each character position pulse represents a different characterreaching a definite drum rotational position, the pulses constituteinfomation which allows the printer electronics to energize the printhammer solenoid as the desired character moves in front of the hammer,or to actuate different machine functions if the received code signalcombination are function signals.

The print hammer carriage 54 is stepped across in front of the drum 52and parallel to the drum axis by spacing mechanism actuated by a spacingsolenoid 6I? mounted at the right-hand side of the printer. Carriage 54is power driven to a start-of-line position at the left-hand margin by acarriage return mechanism 62, seen at the left hand side of FIGURE 1.Carriage return mechanism is activated by the carriage return magneticclutch 64, power for carirage return being derived, through clutch 64,from the printer motor B1.

Shown diagrammatically in FIGURE 2, a sheet paper strip record medium 65is supplied from a paper roll 67 mounted behind the drum 52, the paperstrip feeding over suitable glide devices (not shown), under and up pastthe front of the drum 52, passing between the drum S2 and the printhammer carriage 54 and under two side edge top guide lingers (notshown). The paper strip 65 then passes on out of the top of the printerunit Sti.

Paper feed is enabled by cooperation of two large friction banded feedWheels at the ends of the drum and two presure rolls (see FIGURE underthe drum which press the paper against the two large feed wheels whichare selectively, incrementally driven.

Seen in skeleton form in FIGURE 1, an ink ribbon 69 Y passes across theduim face parallel to the drum between the print hammer and the paper totransfer the typed impresion from the drum to the page during a printoperation. The ink ribbon assembly feed and reverse mechanism isconventional and details are not shown. However, the ink ribbon 69 inthis printer passes in a straight stretch across the front of the drum52 parallel to the character spacing pathof the print hammer, and theentire straight stretch of the ink ribbon if desired can be lowered andlifted by action of a ribbon lift solenoid 71 to a position in front ofthe hammer just prior to each printing action. This operation enablesviewing of the line being printed without its being obscured by apermanently placed stretch of ink ribbon. Mechanism to accomplishthisribbon lift is not a part of this invention.

The printer components are mounted on a support structure which includesa thick base plate 66 (FIGURE 2) incorporating a slotted center track 68(FIGUREI) which passes lateraly from one side of the printer to theother and under the path of travel of the print hammer carriage 54. Twovertical side plates 70 and 72 (see FIG- URES 3 and 5) are rigidlysecured to the base plate 66 and provide mounting structure for most ofthe printer components. Support structure details are not shown in diFIGURE 1, but portions of the base plate and side .plates can be seen insome of the other figures.

The printer electronics is preferably transistorized and mounted eitherin a module 51 (FIGURE 2) on the back of the printer mechanics orincorporated in large printed circuit boards secured on the underside ofthe printer frame stucture.

The electric drive motor B1 supplies -rotational driving power to theprinter mechanism Sti by means of a drive belt 11S which connects themotor to the drum shaft, a function power shaft and a carriage returnclutch. Drive belt 118 passes around a drive pulley 116 attached to themotor shaft and to three driven pulleys 118, 120 and 122, pulley 12)being later referred to in more detail. To prevent slippage, the drivebelt is notched and engages corresponding ygear teeth in each pulley.

Referring particularly to FIGURES 1, 3 and 5 the print drum 52 ispreassembled in an lightweight inexpensive manner from a plurality ofdiscs, preferably double type row wheels 76, manufactured to very closetolerances. A desired number of type wheels 76 are placed on the drumshaft 74, indexed t-o align all characters and clamped together by twoend clamping plates 78, adjacent spacers 80 and nuts 82, the latterbeing threaded and torqued very tightly on intermediate threadedsections of the drum shaft 74. Both sets of clamping plates 7S, spacersSi? and nuts S2 are suitably locked together, after the clampingpressure is achieved. This construction is described and claimed inco-pending applications Ser. No. 184,820, filed April 3, 1962 and Ser.No. 481,796, led Aug. 22, 1965.

The clock wheel 58 is non-rotatably secured to the right-hand end ofdrum shaft 74 and has peripheral character reference notches 124properly located relative to the angular positions of the printcharacters on the drum 52 and one index notch 126 located radiallyinside of the path of notches 124. The positioning of the monitor headsand 92 will provide one indexing pulse and 64 reference pulses onceduring each rotation of the print drum 52, although the index pulse isutilized only whenever the print drum starts to rotate. As the clockwheel 58 rotates with the print drum 52, the moving notches vary thereluctance of bar type magnets located in the clock monitor head coils90' and 92 inducing appropriate current pulses into associatedtransistor amplifiers which are not described herein.

A left-hand bearing retainer assembly is placed over the left-hand endof the drum shaft '74. A somewhat similar right-hand bearing retainerassembly 84 (FIG- URE 3) and shaft bearing are placed over the righthandend portion of drum shaft 74. The right-hand bearing assembly 84, shownin FIGURE 3, is telescoped over a sleeve boss 86 which is integral withand projects from one side of a clock head mounting and timing disc 88.The disc 3S mounts the two printer clock monitor heads 99 and 92 indesired positions, as diagrammatically illustrated in FIGURE 1. By meansof the two adjusting screws 93 and 93', illustrated in FIGURE 4, theangular position of the timing disc 38 relative to the print line can beadjusted to make incremental changes of the index and reference pulsecount positions.

The drum end bearing retainers are clamped in sockets on top ofrespective printer frame end plates 70 and 72 by clamping caps such asthe right-hand clamp cap 94 seen in FIGURES 3 and 4. The right-hand endplate cap 94 has two spaced apart lugs 95 on its outer face, the lugshaving threaded bores that receive the two opposed timing disc adjustingscrews 93 and 93', the ends of Ewhich engage an integral angularpositioning finger 97 on the timing disc S8. Adjusting screws 93 and 93are locked in adjusted position by lock nuts 99.

The purpose of the timing disc adjustment is to insure proper timecorrelation between the received character coincidence count pulse fromthe character clock head to the printer electronics and the printstrokes of the hammer or hammers, correlation vdepending upon theangular fixed position of the clock heads, so that the printedcharacters are not cut olf at the top or bottom as depicted in FIGURE 3.

Referring to FIGURES 3 and 5, before the hubs of the drum end bearingretainers are positioned and clamped in their sockets -by the clampcaps, left and right-hand record medium feed wheels 96 and 98, withassociated ring gears 100 and 102 are placed on external bushing sleevesmade integral with the associated bearing retainers. The feed wheelgears may be integral or separable from the feed wheels. In the lattercase they are clamped to the respective feed Wheels 96 and98 by screws104. In either case split annular ring clamping plates 106 could befastened to the sides of feed wheels 96 and -98 and fit into and rideinv grooves 108 in the non-rotatable end bearing retainer body, therebyaxially maintaining the feed Wheels 96 and 98 in desired positionsadjacent each end of and rotatable relative to the print drum.

A rubber ring 110 is stretched over the periphery of each :feed wheel 96and 98 land fitted into half circle 4grooves 112 in the periphery of itsfeed wheel. The rubber ring can be preformed or it is cut or ground downso its outer periphery is almost even with the feed wheel periphery,thereby serving as a friction tire or band to engage and line feed thepage record medium, by means to tbe hereinafter described. Note, thefeed wheels are rotatably mounted on the bearing retainers which in turnare clamped in adjacent printer frame end plates 78 and 72 and the shaftof the print drum 52 is rotatably mounted in and extends through thebearing retainers. Drum and feed wheels rotate completely independent ofeach other.

The left-hand end of the drum shaft 74 projects beyond the left-handframe end plate 70 and a gear toothed pulley 114 is non-rotatablysecured thereto by set screws. Turning back to FIGURE 1, the printermotor B1, which will be mounted on the printer support structure insideof frame plate 70, is disposed with its shaft .parallel to the drumshaft 74 and carrying a toothed drive pulley 116. The notched drive belt118 meshes with the teeth in motor pulley 116, and with the other threepulleys, the drum pulley 114, a function shaft pulley 120 and a carriagereturn clutch input pulley '122. As has been described hereinbefore,whenever the printer motor B1 is energized, the drum 52 will becontinually rotating, and printing occurs on-the-ily.

Line feed- Referring generally to FIGURE l and specifically to FIGURES5-8, the record paper 65 is fed through the printer one line (or more)at a time by the action of the line feed mechanism 138, differentspacings of line feed being easily and conveniently changed, as will behereinafter described.

Looking at FIGURE l, the motor driven belt 118, through the power shaftpulley 120', rotates the power shaft 121 which extends parallel and tothe rear of drum 52 to the right-hand side of the printer mechanisms.Power shaft 121 is continually rotating and provides power for both theline feed and the ribbon feed and reverse mechanisms. The ribbon feedmechanisms (not shown) is operated continuously by the power shaft, andthe line feed mechanism? 138 is selectively cyclically operated throughthe action of a positive action startstop clutch mechanism 142whichcouples the right-hand end of power shaft 121 to a line feed cam144.

Detailed construction of a suitable start-stop power shaft clutch isshown and described in Kleinschmidt et al. U.S. Patent No. 3,009,988(see FIGURES 29-32 of that patent). Although the clutch stop plate ofthat disclosure uses only a single stop lug to accomplish 360 start-stopcycling, two lugs at diametrical positions' will enable 180 start-stopcycling.

FIGURE 6 illustrates the positive clutch 142 just after its plate isreleased so that the clutch is engaged to cam 144 and the cam hasstarted to rotate. To accomplish clutching, the line feed solenoid 146is energized, attracting the armature end 148 of the clutch stop lever150, which pivots stop lever 150 clockwise on post 152 against the biasof spring 154 and removes the stop lever blocking end 154 from blockingposition in front of clutch plate lug 156. This unblockng of the clutchplate 158 permits the clutch to make a positive connection between thepower shaft 121 and feed cam 144, driving the line feed operating camthroughk180 degrees.

The line feed solenoid 146 is only momentarily energized (10 ms.) andlong before the feed operating cam 144 can complete avhalf revolution,it has released the stop lever armature 148 which returns to its springbiased blocking position where lever blocking end 154 is engaged by thenext stop lug 156 of clutch plate 158. Blocking of clutch plate 158disengages the clutch 142 at the end of the half revolution. A clutchdetent arm 159 and detent cam 160 fixed to the feed cam 144 ensures thatthe clutch 142 remains disengaged until the stop plate 158 is againreleased.

Line feed operating cam 144 is a dual cam, as shown in FIGURES 6 and 7,having two opposed identical radial rises 162 followed by abruptdrop-offs into identical dwells 164. A roller 166 on the end of a springbiased cam follower arm 168, disposed in the path of the cam lobes willbe engaged by the operating cam and will make the follower arm cycleonce for each 180 of operating cam rotation.

Shown in FIGURE 7, cam follower arm 168 is secured to a link 170 to forma dog-leg bellcrank pivoted on lpost 172. The cam follower bellcrank hasa spring anchor finger 174 connected to one end of biasing spring 176,the other end of which is anchored on a post fixed to a support Vbracket178. Spring 176 urges the cam follower counterclockwise so its roller166 is urged toward the periphery of the feed operating cam 144.

Turning again to FIGURE 5, it will be seen that the aforedescribed feedwheels 96 and 98 at the ends of the print drum, advance the paper byrotation while pressing the paper against two pressure rollers 180 and181. The two pressure rollers 180 and 181 are mounted on flat springs182 which are fixed to a pressure roller release shaft 183. Attached tothe pressure roller release shaft is a pressure release lever (notshown). When the pressure release lever is moved to the rear of theprinter and latched, the pressure roller release shaft is rocked to movethe pressure rollers 180 and 181 into spring biased engagement with theleft and right edge portion of the paper record strip, pressing thepaper record tight against the high friction, paper feed wheel lbands110, thereby enabling controlled line feeding of the paper, by powered,incremental, simultaneous rotation of the two feed wheels 96 and 98.

Parallel to the drum axis and passing under the drum 52, and toward thefront of the printer is a line feed shaft 186 rotatably 4mounted onbrackets 188 and 190 secured to the printer frame. Shaft 186 extendsthrough the righthand end plate 72 and through yand projects beyond itsright-hand support bracket 190. Right and left line feed driving gears192 and 193, non-rotatably attached to the `line feed shaft v186, meshwith and impart incremental drive to the gears 100 and 102 which arefastened on the paper feed wheels 96 and 98.

The paper record is rmly held in a given position or it can be fed oneor more lines at a time by stepping a line feed ratchet wheel 194non-rotatably secured on the projecting right-hand end of the line feedshaft (FIG- URES 5 and 7).

To keep the paper from inadvertently line feeding during printing, theratchet wheel 194 is detained in its rotational position by aconventional line feed detent 196 shown in FIGURE .7. During line feedoperation, the ratchet wheel 194 is turned one or two (or more) spacesby a spring Vbiased line feed pawl 198 pivotally mounted on a line feedpawl bail 200. Bail 200 is 4axially maintained and rotatably pivotallymounted on the projected end of line feed shaft 186, by a collar.

A post 202, fixed in one arm of pawl bail 200 is engaged by -a forkedend 204 of the cam follower link 170 thereby enabling rocking movementof the feed cam follower to concurrenty rock the pawl bail 200 about theaxis of line feed shaft 186. Counterclockwise rotation of the feed pawlbail 200 causes the line feed pawl 198, which is always biased intoengagement with the teeth of the feed ratchet wheel 194, to positivelyrotate the feed shaft 186 against the detent action of the line feeddetent 196. After the paper record is fed, by rotation of feed shaftA186, the line feed detent 196 engages a tooth of the ratchet wheel 194to prevent further inadvertent movement of the line feed gears. As thepawl bail 2&0 completes the return stroke of its cycle, pawl 198ratchets back over the teeth of ratchet wheel 194.

The angular increment of rotation of the pawl bail 200 and thence,through pawl 198, to rotate the line feed shaft 186, depends upon theinitial position of the earn follower roller 166 relative to the lowdwell 164 of line feed operating cam 144. This initial position can bechanged by changing the setting of a selector knob 206, FIGURES 7 and 8,to permit one, two or three lines to be fed per line feed solenoidoperation. Knob 206 is formed on the end of a cylinder 208 with athrough bore 210 enabling the cylinder to be rotatably disposed on afixed post 212 under the lateral spring biased forked arm 174 of the camfollower bellcrank. Cylinder 208 is axially retained on post 212 byscrew 214, but can be manually rotated on the post to a plurality ofangular positions as determined by a spring loaded ball detent 216located in an eccentric blind bore in the end of cylinder 208. The balldetent 216 is biased against the mounting pate 178 and engages anassociated one of a number of small holes 218 located on a circular arcin plate 178, depending upon the selection.

In FIGURE 7, the knob 206 is positioned with the number 3 uppermost,indicating that each line feed operation will result in the feeding ofthe paper record, a distance of three lines. In the number 3 position, alarge cam fiat 220 (see FIGURE 8) on selector cylinder 208 is disposeddirectly under a cam follower portion 222 of the bellcrank spring arm174 which in the inoperative condition, is biased against the surface ofcylinder 208 which is positioned uppermost, i.e., the cam flat 220. Thispermits the line feed bellcrank to rock counterclockwise a distance thatdrops the carn follower roller 166 all the way to the Ibottom of `a linefeed operating cam lower dwell 164. Subsequent 180 rotation of line feedcam 144 resulting from energizing ofthe line feed solenoid 146 will liftthe roller 166 to the top of a line feed cam rise 162 causing aclockwise power movement of the bellcrank follower sufficient to rockthe pawl bail 200 counterclockwise a distance through which the pawl 198drives the feed shaft 186 an angular increment to feed the paper threelines.

If the selector knob is set with the number 1 uppermost, the springbiased forked arm 174 of the cam follower lbellcrank will hit a highsurface 224 on cylinder 208 and cannot move counterclockwise underspring bias as f-ar as it did in selector position 3. Therefore the camfollower roller 166 will not drop all of the way into a lower dwell 164of the operating cam 144. Now, subsequent 180 rotation of operating cam144 will only rock the cam follower under positive power :a smallincrement (about 1/3 of that previously described for setting number 3)resulting in movement of the feed pawl 198 an amount sutiicient only `toline feed the paper one space.

If the selector knob 206 is placed in position 2 the intermediate mediumdepth flat surface 226 is placed under the cam follower spring biasedarm 174 and the cam follower bellcrank is permitted to rock through anangle halfway between that of a single line feed and a triple line feed,i.e., it will result in a double line feed. This selector mechanism is avery simple device for varying the length of line feed pawl powerstroke, resulting in less work being performed for a single feed actionthan for a double or triple feed action. it is to -be understood thatmore than the three variations of line feed could be accommodated merelyby suitably shaping the line feed operating earn 144 and the cam a'ts onthe selector cy'linder 203.

The invention may be embodied in other specific forms without departingfrom the spirit or essential characteristics thereof. T he presentembodiment is therefore to be considered in all respects as illustrativeand not restrictive, the scope of the invention being indicated by theappended claims rather than by the foregoing description, and allchanges which come within the meaning and range of equivalency of theclaims are therefore intended to be embraced therein.

What is claimed and desired to be secured by Letters Patent is:

1. For use in a page record printer, a line feed mechanism for feeding apage record stepwise one or more lines spaces at a time including: pagerecord engaging and feeding means; a ratchet wheel drivingly connectedto said record engaging and feeding means; a ratchet wheel advancingpawl means :pivotally mounted adjacent and in engagement with the teethof said ratchet wheel; a selectively operable, power driven cyclingmeans for imparting a power and a return stroke to said pawl means; andmeans to selectively vary the magnitude of return stroke of said pawlmeans to thereby control the magnitude of power stroke and work appliedto said pawl means by said power driven cycling means and chan-ge themagninitude of line feed.

2. A line feed mechanism as defined in claim 1, wherein said powerdriven cycling means comprises a startstop power cam, and a pivotallymounted cam follower arm, spring biased toward said power cam andconnected to rock said pawl means; and said means to selectively varythe magnitude of said pawl means return stroke includes a controlmem-ber, having a plurality of abutment surfaces adapted to |beselectively positioned in the return stroke path of a kinematic linkagewhich comprises said pawl means and said follower arm to block thereturn stroke movement of said pawl means at `different magnitudes ofreturn stroke.

3. A line feed mechanism as defined in claim 1, wherein said powerdriven cycling -means comprises: a power driven, continuously rotatingshaft; a rotatable cam c0- axially mounted relative to said power drivenshaft; a selectively operable, solenoid controlled start-stop cyclingclutch coupling said power driven shaft and said cam; Iand a camfollower pivotally mounted adjacent said cam for engagement by said camand connected to said pawl means to enable rocking said pawl means todrive said ratchet.

4. For use in a [page record printer, a page record line feed mechanismcomprising: rotatable page record engaging and feeding member rotatingmeans; a ratchet wheel coaxially, non-rotatably secured on said rotatingmeans; a ratchet wheel advancing pawl means pivotally mounted adjacentand in engagement with the teeth of said ratchet wheel; a selectivelyoperable, power driven cycling means for imparting :a power and a returnstroke to said pawl means; and means to selectively vary the magnitudeof return stroke of said pawl means to thereby control the magnitude ofpower stroke and work applied to said pawl means by said power drivencycling means and change the magnitude of line feed; said power drivencycling means including a power driven, continuously rotating shaft, arotatable cam with high and low dwells coaxially mounted relative tosaid power driven shaft, a selectively operable, solenoid controlledstart-stop cycling clutch coupling said power driven shaft and said cam,a cam follower pivotally mounted adjacent said cam and connected to saidpawl means to rock said pawl means, and spring biasing means connectedto said cam follower and biasing said cam follower toward said cam.

5. A line feed mechanism as deiined in claim 4, wherein said camfollower is a -bellcrank with a cam `following means on one arm, itsother arm vbeing connected to said pawl means, and an a-butment stopsurface on one of said arms; spring means are connected to saidbellcrank to bias its follower arm toward said cam; and said means toselectively vary the return stroke of said pawl means constitutes aselectively shftable stop member of said abutment stopv located in thepath of movement surface in the direction biased by said spring means,different shifted positions of said stop member varying the limitedposition ofthe spring ybiased return stroke of said bellcrank andconnected pawl means.

`6. A line feed lmechanism as dened in 4claim 5, wherein said shiftablestop member is a manually rotatable cylinder means having a plurality ofsurfaces located at dilerent ditsances from the axis of said cylindermeans and shiftable into position to `be abutted lby said abutmentsurface by incremental rotation of said cylinder means.

7. A line feed mechanism as defined in claim 6, wherein a fixed supportplate is provided to rotatably mount said cylinder means, said cylindermeans is axially maintained with one end closely adjacent said plate,and detent means in said cylinder means and said plate cooperate tomaintain selected positions of said cylinder means.

References Cited UNITED STATES PATENTS 2,038,929 4/1936 Fisher 741-1242,561,755 7/1951 Recker 74-l24 X 2,965,204 12/1960 Howard 192-27 XMILTON KAUFMAN, Primary Examiner.

`FRED C. MATTERN, Examiner.

20 F. E. BAKER, Assistant Examiner.

1. FOR USE IN A PAGE RECORD PRINTER, A LINE FEED MECHANISM FOR FEEDING APAGE RECORD STEPWISE ONE OR MORE LINES SPACES AT A TIME INCLUDING: PAGERECORD ENGAGING AND FEEDING MEANS; A RATCHET WHEEL DRIVINGLY CONNECTEDTO SAID RECORD ENGAGINGB AND FEEDING MEANS; A RATCHET WHEEL ADVANCINGPAWL MEANS PIVOTALLY MOUNTED ADJACENT AND IN ENGAGEMENT WITH THE TEETHOF SAID RATCHET WHEEL; A SELECTIVELY OPERABLE, POWER DRIVEN CYCLINGMEANS FOR IMPARTING A POWER AND A RETURN STROKE TO SAID PAWL MEANS; ANDMEANS TO SELECTIVELY VARY THE MAGNITUDE OF RETURN STROKE OF SAID PAWLMEANS TO THEREBY CONTROL THE MAGNITUDE OF POWER STROKE AND WORK APPLIEDTO SAID PAWL MEANS BY SAID POWER DRIVEN CYCLING MEANS AND CHANGE THEMAGNINITUDE OF LINE FEED.